Using standard navigational position fixes, the mission plotted observations inflight on a chart as they proceeded and transmitted them to Beane Field for relay to Waller and Borinquen Field, Puerto Rico.
32.
Using a hand-held GPS plotter from Panasonic, I got position fixes, steering information, speed, range to destination and other data from a system of military satellites 12, 000 miles above Earth.
33.
Its role is to provide a mark warning of the reefs and rocks to the west of Guernsey and providing a position fix for vessels entering the Channel Traffic Separation Scheme.
34.
Without compensating for time dilation and other relativistic effects, GPS position fixes would be out by as much as 15 metres ( see GPS # Relativity ) and-woah, you've just missed your turning!
35.
However, when Hegenberger tried to obtain a position fix by radio direction finding, the transmitter signal from the " Bird of Paradise " was too weak for the ship to obtain a bearing.
36.
Room 40 was able to observe, using intercepted wireless traffic from Zeppelins which were given position fixes by German directional stations to help their navigation, that the accuracy of British systems was better than their German counterparts.
37.
Radio contact with " Swan 38 " was lost after 22 : 00 on 12 October 1974, apparently as the aircraft was heading into the typhoon's eye to make a second position fix during its alpha pattern.
38.
This method correctly deduces the full week number if the receiver is never allowed to remain shut down ( or without a time and position fix ) for more than 1, 024 weeks ( ~ 19.6 years ).
39.
Because SA affects every GPS receiver in a given area almost equally, a fixed station with an accurately known position can measure the SA error values and transmit them to the local GPS receivers so they may correct their position fixes.
40.
On the other hand, a mobile device with a GPS chipset requires no data connection to capture and process GPS data into a position solution, since it receives data directly from the GPS satellites and is able to calculate a position fix itself.
